Index: Ringtoets/HydraRing/src/Ringtoets.HydraRing.Calculation/Calculator/IStructuresCalculator.cs
===================================================================
diff -u -r470f6846d3dcd6f759a48d838cee8d1b9bbdeac7 -rd02c314b35f0c122d7ac466dbe384e6b2707a1fd
--- Ringtoets/HydraRing/src/Ringtoets.HydraRing.Calculation/Calculator/IStructuresCalculator.cs	(.../IStructuresCalculator.cs)	(revision 470f6846d3dcd6f759a48d838cee8d1b9bbdeac7)
+++ Ringtoets/HydraRing/src/Ringtoets.HydraRing.Calculation/Calculator/IStructuresCalculator.cs	(.../IStructuresCalculator.cs)	(revision d02c314b35f0c122d7ac466dbe384e6b2707a1fd)
@@ -19,6 +19,7 @@
 // Stichting Deltares and remain full property of Stichting Deltares at all times.
 // All rights reserved.
 
+using System;
 using Ringtoets.HydraRing.Calculation.Data.Input;
 using Ringtoets.HydraRing.Calculation.Data.Output.IllustrationPoints;
 using Ringtoets.HydraRing.Calculation.Exceptions;
@@ -63,6 +64,7 @@
         /// <param name="input">The <see cref="TInput"/> which contains all the necessary input
         /// for the calculation.</param>
         /// <exception cref="HydraRingCalculationException">Thrown when an error occurs while performing the calculation.</exception>
+        /// <exception cref="InvalidOperationException">Thrown when preprocessor directory is required but not specified.</exception>
         void Calculate(TInput input);
 
         /// <summary>